1. Field of the Invention
This invention is in the field of portable electroplating applicators of the type used for the repair and maintenance of aircraft parts and the like and provides a structure which is capable of being used in narrow places. It consists of an anode structure composed of a soft metal to be plated which is locked to an overlying harder metal by flattened portions of protuberances extending from the soft metal anode through the apertures in the backing metal.
2. Description of the Prior Art
In commercial tank plating, the anode is static so that there are no problems in maintaining the shape of the anode during plating. In portable or tankless electroplating, the workpiece is static and the anode is rubbed in or on areas to be plated. This type of plating involves no real problem with harder metals such as zinc, copper and the like, which have melting points of 420.degree. C. and more, since such metals are self-supporting and they do not require a backing to prevent bending during plating. Such anodes can be made in one piece, sheared from a sheet or plate, and require only an offset bend to accommodate a wood, plastic, or other electrically non-conductive handle containing a flexible lead. Such anode structures involve no serious problems in maintaining purity of plating.
However, using soft metals having melting points of 327.degree. C. or less, and Brinell hardness numbers of less than 20, such as lead, cadmium, tin, and indium, provides problems because these metals require a stiff metal backing to prevent bending during plating. It is not possible, for example, to use steel rivets or bolts to secure the soft metal anode to the backing because the presence of such dissimilar metals adversely affects the plating. To prevent contamination of the platings with unwanted metals, the backing must be insoluble under all plating conditions, and under conditions of heat generated in the anode during the plating process.
Portable electroplating devices have been described in several of my previously issued U.S. patents. In U.S. Pat. No. 3,525,681 there is described an electrolytic device for applying an electric current through an electrolyte to a metal surface, the device including absorbent sleeves which hold liquid electrolyte against the anode for plating purposes.
In U.S. Pat. No. 3,746,627, there is described a method of metal electroplating for depositing a localized plating on an electrically conductive portable member. The workpiece to be plated is removably positioned on an electrically conductive current carrying cathode bar. The contact area to be plated is rubbed with a plating electrolyte-carrier to wet the area with the electrolyte and build up a plated layer.
In my U.S. Pat. No. 3,755,089, there is described a method of gold plating wherein the surface to be plated is first cleaned and activated without any current being applied by rubbing a non-displacement type of gold electrolyte solution thereon by means of a sleeve-covered anode. The plating current is then passed through the electrolyte solution during continued rubbing to effect the plating with gold on the surface as the cathode.